DIESEL BLACK SMOKE 1981-82 VEHICLES

WHEN INVESTIGATING COMMENTS OF EXCESSIVE BLACK SMOKE FROM DIESEL ENGINES AT 1/3 TO 1/2 THROTTLE OPENINGS, CHECK OPERATION OF E.P.R. AND V.R.V VALVES. EXCESSIVE E.P.R. PRESSURE CAUSES HIGH E.G.R. FLOW, DILUTING INTAKE AIR WITH EXHAUST GAS AND STARVING ENGINE FOR OXYGEN RESULTING IN BLACK SMOKE. ANOTHER SOURCE OF INTAKE AIR DILUTION COULD BE A LEAK AT EITHER OR BOTH SIDES OF THE INTAKE CROSSOVER GASKET.

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